Retail grocery stores and fast food restaurants purchase for resale specified pieces of fowl such as chicken breasts, wings, and legs. To meet this commercial demand, poultry is dismembered automatically in commercial poultry processing plants and the various pieces are packaged and sold separately or collectively.
Heretofore, chicken wings have been severed from the torsos of previously eviscerated poultry with rotary blade means. U.S. Pat. No. 2,941,238 discloses an early concept of using a rotary blade wherein the shoulder joint of a chicken is laid upon a slotted rod along which a rotary blade is passed. In this case the wings were to be completely severed from the torso. In other cases, such as the procedure disclosed in U.S. Pat. No. 3,942,222, the muscle that overlies the ball and socket of the shoulder joint of a bird is to be cut without complete severence of the wings from the torso so as to enable the wings to be folded in a manner to facilitate packaging. Stationary blades are disclosed as being used to effect the cutting action.
More recently, in an attempt to increase process speed, various rotary knives, rotary saws and pivoting blades have been used to sever poultry wings from the carcasses; however, there is still the hazzard of leaving in the meat pieces of loose bone cut from the joints. Since bone fragments are difficult to observe and to remove, they usually have been left in the meat with the possibility of their being encountered upon the product being eaten by a consumer.
In an attempt to reduce the risk of the creation of bone fragments in cut-up poultry, machines similar to that illustrated in U.S. Pat. Nos. 4,016,624 and 4,424,608 were devised. With these machines the birds were to be removed from the overhead conveyor after the birds had been eviscerated and the backs of the carcasses were to be carried on a conveyor for movement through a succession of dismembering stations in an automated processing line. Stationary knifes provided adjacent the path of movement of the birds severed the main tendon between each of the inner ends of the wing stubs and the back which holds the ball on the inner end of the wing stub operable within the socket. The severence of this tendon by the blade at each side of the carcass was to be done in a manner proportedly to eliminate the possibility of objectionable bone chips being formed during the severance operation. However, in processing poultry in this manner, each bird must be removed from the overhead conveyor and individually carried through the processing station.
Although the dismembering of birds as they move on an overhead conveyor has been attempted in the past, as disclosed in U.S. Pat. Nos. 4,271,561 and 4,354,296, the automatic removal of wings from the poultry carcasses as the birds remain suspended from an overhead conveyor generally has been unsuccessful.
Obviously it would be a distinct advance in the art if a method and an apparatus were devised for severing the wings from the carcasses of poultry without substantial creation of bone chips from the shoulder joints, without having to dismount the birds from their shackles and to remount them on a conveyor of another machine for the wing severence step, and in a manner permitting breast meat to be deboned in full butterfly with tendons intact. Unfortunately, such a process and apparatus for automatically performing such a process has heretofore eluded the industry in view of the difficulty in precisely presenting shoulder joints to cutting blades of birds that are swinging free from overhead shackles. Accordingly, it is the provision of such a method and apparatus to which the present invention is primarily directed.